This application is related to U.S. patent application Ser. No. 08/328,754 entitled CONNECTOR FOR A SELF CONTAINED LASER GYRO and U.S. patent application 08/328,755 entitled COMBINED SUPPORT PLATE AND PRINTED WIRING BOARD FOR A SELF CONTAINED LASER GYRO filed on the same day by the same inventors and commonly assigned with the present application.
This invention is directed to the field of laser gyros and more particularly to a laser gyro which is contained in a package with its support electronics.
Laser gyros have attained wide acceptance as high quality, high accuracy navigation devices. Systems which originally used ring laser gyros could occupy an area of four cubic feet or more and generally weighed several pounds.
Such a large system would not work in certain applications, such as missiles and satellites. Only a small, lightweight navigation system will work in these circumstances.
Accordingly, small laser gyro systems have been developed, such as the Honeywell GG1308, which is described in IEEE PLANS 1990, 20 Mar. 1990, pp 528-536 GG1308 Ring Laer Gyro Inertial Measurement Systems-Honeywell's Low Cost Solution For Tactical Applications, by J. M. Oelschlaeger and L. O. Thielman. Such a laser gyro has size and weight advantages. But these advantages come at the expense of performance.
Larger gyros, which generally provide better performance, have been previously packaged such that only the laser block itself with any onboard circuitry is packaged within a hermetically sealed container. Other electronics were connected to the laser block, but resided outside the sealed container. Making connections to the block while retaining the seal thus became difficult.
Further some laser gyros employed a dither motor to overcome problems associated with lock-in of the laser beams. These laser gyros also generally included electro-mechanical pickoff devices. In these laser gyros, a dither drive and pickoff cable assembly was bonded to the laser block. This cable assembly was very delicate and clumsy to handle. The cable assembly sometimes also included other sensitive signal wires which occasionally broke during the gyro build process. Further, the cable assembly, when bonded to the gyro block, caused performance problems due to bending of the laser block.
It therefore became desirable to have a high performing, laser block co-located within the hermetically sealed container with its major support subsytems such as the power supply, path length control circuits, laser intensity monitor circuits and the like. This was to be accomplished while maintaining a small, lightweight system. It was yet a further goal to modify the cable assembly to improve the noted wiring and performance issues.